1. Field of the Invention
The present invention relates to a security sensor system including a security sensor, made up of an object detecting subunit for detecting an object and a wireless transmitter, and a receiver for receiving a signal transmitted wireless from the wireless transmitter.
2. Description of Related Art
As shown in FIG. 7, the conventional security sensor system has been known, which includes a security sensor assembly 101, made up of a light projecting unit 102 for projecting infrared rays of light (IR) within a warning area and a light receiving unit 103 for receiving the projected infrared rays of light (IR), both of which are secured to respective supports such as, for example, mounting poles or outer walls of a building, and a receiver 118 disposed, for example, indoor and connected with the security sensor assembly 101 through a connecting cable W. In this conventional security sensor system, when an object intercepts the infrared rays of light within the warning area, an object detecting subunit 110 of the light receiving unit 103 detects the Object and then outputs a warning signal based on this, which warning signal is subsequently received by the receiver 118 through the connecting cable W. The security sensor system has also been known in the art, which includes a PIR (Passive Infrared Ray) security sensor, made up of only a light receiving unit for detecting infrared rays of light emanating from an object, and a receiver connected with this security sensor through a connecting cable. (See, for example, the Patent Document 1 listed below.)
This system generally operates under a security mode during the nighttime or the absence from home, but under a non-security mode during the daytime or the presence at home without performing any warning output (alarming or warning by way of sounds, light or signals) of a human body detection even though a signal input occurs from the sensor. Accordingly, the receiver receives the warning signal, outputted during the security mode, and provides a warning output, but no warning output occurs even though it receives the warning signal outputted during the non-security mode. It has, however, been found that where the security sensor assembly 101 of the AIR (Active Infrared Ray) system and the receiver 118 are connected with each other through the connecting cable, as shown in FIG. 7, so that when during the non-security mode an intercepting object such as, for example, a vehicle is placed within the 10 detection area, the warning signal is continuously (in a hold state) outputted to the receiver, connected with it through the connecting cable, during the interception by the intercepting object as shown in chart (a) of FIG. 8. When the non-security mode is subsequently switched over to the security mode, the receiver 118 receives this signal and the presence of an abnormality can be ascertained.
Even where during the non-security mode such an abnormality detection signal indicative of the detection of an abnormal condition of the sensor as, for example, a tamper signal, which is continuously outputted from the tamper signal output subunit 113, shown in FIG. 7, as a result of a tamper switch being switched on or off upon removal of a sensor covering in an attempt to conduct any interference, is outputted, the abnormality can be ascertained when the non-security mode is switched over to the security mode.
[Patent Document 1] JP Laid-open Patent Publication No. 2001-56887